1971 Volume 8 Issue 6 Pages 297-305
As a factor in the development of anemia in the aged, commonly termed till now“a physiological anemia” due to the absence of direct causes of anemia such as deficiency of hematopoietic substance, V. B12 and iron, hemolysis, malignant tumor, and chronic disease, we have found sclerosis of the bone marrow arteries at autopsy and proposed the following sequence of events: disturbance of the blood circulation, fatty changes and development of anemia. Under the working hypothesis that artericsclerosis of the bone marrow artery is an important factor in the development of anemia in the aged, the present study was undertaken.
As experimental animals, male albino rabbits weighing more than 2kg were used. The animals were maintained on 10g of lanolin and glucose along with bean-curd refuse daily and either subjected to an operation for the production of stenosis of the femoral artery or repeatedly injected intramuscularly with adrenalin, a vasoconstricting drug, to prepare arteriosclerotic rabbits. Peripheral blood examination, determination of serum total cholesterol and body weight measurements were pericdically performed. Animals were used for the experiment at a stage when anemia, hyperlipemia and atherosclerosis of the aorta at autopsy would be demonstrable.
Results: Micropaque was injected into the bone marrow blood vessel of arteriosclerotic rabbits to study the pathological findings, flexion, tortuosity, and narrowing of the bone marrow blood vessel, consequently a decrease of blood flow through the bone marrow was suggested, showing a distinct difference from the normal group. At the site of narrowing of the arterial blood vessels, intimal thickening of the bone marrow artery, narrowing of the lumen, atrophy of the venous sinus and increase of perivascular fatty marrow were noted histologically as in the bone marrow of the aged. Only a small amount of opaque media entered.
The mechanism for bone marrow hypoplasia or increase of fatty marrow in the aged might be explained by the occurrence of sclerosis of the arterial system leading to narrowing of the lumen and subsequent circulatory disturbance, anoxia of the hematopoietic tissue only supplied by the venous sinus and collective sinus, deficiency or interruption of the supply of hematopoietic substance, and eventually atrophy and hypoplasia of the hematopoietic site and fatty marrow corresponding to the terminal artery, since the whole blood stream via the nutrient artery of the bone marrow and artery capillary communicates with the main venous system exclusively through the venous sinus and collective sinus.
These results would tend to indicate that the anemia in rabbits with experimentally induced hyperlipemia and arteriosclerosis resembles the anemia in aged human subjects especially as to the bone marrow findings. Sclerosis of the bone marrow artery appears to represent a factor in the development of such anemia.